Transmission



Nov. 17, 1.942. H. R. GREENLEE ETAL TRANSMISSION Filed June 25, 1941 2Sheets-'Sheetl l Nov. 17, 1942. l|| R GREENLEE ET AL 2,302,312

TRANSMISSION Filed June 25, 1941 -2 Sheets-Sheet 2 ma@ 12. Gmlee LorenlQriory' JolRn ovul V lNvENToRs A ATTORNEY Patented Nov. 17, 1942TRANSMISSION Harry R. Greenlee, Loren D. Britton, and John R. Bond,South Bend, 1nd., assignors to The Studebaker Corporation, South Bend,Ind., a corporation of Delaware Original application December 14, 1940,Serial No. 370,114. Divided and this application June 25, 1941, SerialNo. 399,578

5 claims. (ci. 'x4-368) This invention relates to transmissions and moreparticularly is directed to a transmission for use on automotivevehicles for transmitting torque from the power plant of the vehicle tothe driving axle.

The present application is a division of our copending application,Serial No. 370,114, filed Decemberv14, 1940.

In the copending application referred to above we have disclosed -atransmission embodying a fluid coupling to provide for smooth connectionof the engine to the transmission and incorporating with the couplinglan underdrive control' and a two speed transmission, the planetarydrive being interposed between the fluid clutch and the two speedtransmission and functioning in conjunction with the transmission toprovide four selective driving ratios. I

This combination produces a transmission which corresponds generallywith the present three speed transmission plus overdrive, it beingcontemplated that in the present invention the fourth speed which is avdirect connection between the engine and propeller shaft will becomparable to an overdrive in that the gear ratio on the'driving axle isreduced so that, in effect, the same result is attained with a directdrive as was formerly accomplished through an overdrive.

While the above mentioned copending application disclosed details of thefluid coupling of the planetary overdrive and control therefor forconnectingthe power of the engine to the transmission, the presentinvention concerns itself more particularly with the details of thetransmissionitself, the particular two s transmission herein shown anddescribed being capable of use with other types of fluid clutch andunder drive mechanism and constituting in itself a novel type oftransmission for use in such a vehicle power system, although it is tobe understood that the transmission is equally well adapted for use withother forms of clutches and without the use of the underdrive, ifdesired.

It is highly desirable in a transmission of this type that overrunningof the propeller shaft with respect to the engine shaft be providedduring the sluiting operation so that there is .no braking eect producedby the engine during the shifting operation. The elimination of thiseffect produces a much smoother shift as Well as preventing rapiddeceleration of the vehicle during the time that the accelerator pedalis raised as the shift is taking place. The present inventionacconnection. In addition, the construction is such that if the lowspeed gear in the transmission be shifted into meshing engagement itneed not be removed from its meshing position during shifting into highspeed or direct drive.

Another advantage, however, in connection with this overrunning featureis the provision of means which is automatically operable during theshifting operation and allows the use of the motor as a brake throughthe transmission. This is of advantage in descending hills or inclineswhen the braking effect of the motor can be utilized to retardacceleration of the vehicle. In a transmission in which the overrunningof the propeller shaft with respect to the engine is provided at certainspeed ratios, it is also desirable that a posit-ive reverse drive beprovided and the present invention includes such means, having a gear onthe reverse idler shaft of the transmission which is of the same designas the countershaft gear for producing reverse drive. This gear, inconjunction with a novel type of clutching mechanism, provides apositive reverse drive through the transmission while still allowingoverrunning in any of the forward speeds. In this connection we preferto employ a coil spring clutch of the L. G. S. type which can beenergized in one direction to produce a clutching action by expansion ofthe coil spring, or can be energized in the opposite direction toproduce clutching action by contraction of the springs. If desired,however, a diiferential form of overrunning type clutch may besubstituted, or other types of mechanism can be employed so long as apositive reverse drive is provided.

The two speed transmission herein disclosed is of distinctly noveldesign and is capable of employment either with or without the planetaryunderdrive of the uid coupling. The transmission is arranged with asynchronizer and toothed clutch for producing the desired connectionbetween the drive shaft and transmission tail shaft land is providedwith a splined gear on the countershaft for producing low speed drivethrough the transmission. This splined gear is so arranged as to remainin meshed position when the direct driving engagement is eiiected andconsequently simplifies the shifting action and readily accommodatesthis transmission to an automatic control system.

In addition, the synchronizer sleeve is so arranged in the presenttransmission as to provide means whereby when reversely shifted it willproduce a positive reverse drive 0r may be utilized complishes this byproviding such an overrunning 55 to produce a braking action of themotor on the tail shaft of the transmission to retard the tail shaftduring coasting or when descending long hills.

In a modified form of the two speed transmission we employ only fivegears which will produce forward drive in either one or two speed ratiosand will also produce the reverse drive.

It is contemplated within the purview of the present invention toprovide suitable speed responsive or torque responsive mechanisms on thetail shaft and the transmission which, in turn. are adapted to controlsuitable valve or contact mechanism for automatically effecting thedesired shifting of the transmission. Y The control mechanism, while notshown in the present application. may be of simplied form and may beeither of positive pressure or vacuum actuated type.

Other objects and advantages of the present invention illustrating thesimplicity of design, ease of assembly and details of construction willbe more apparent from the following detailed description which, taken inconjunction with the accompanying drawings, will disclose to thoseskilled in the art the particular construction and operation of apreferred form of the present invention.

In the drawings:

Figure 1 is a sectional view showing one form of the two speedtransmission which is driven through either a conventional clutch or theclutch of the underdrive disclosed in the above mentioned copendingapplication;

Figure 2 is a detailed sectional view of a portion of Figure 1 modifiedto incorporate an overrunning clutch therein;

Figure 3 is a detailed sectional view of a further modification ofFigure 1 in which one of the gears has been eliminated;

Figure 4 is an end elevational view, partly in section, showing therelative alinement of the main shaft, counter shaft and reverse idlershaft of the transmission; and

Figure 5 is a top plan view, partly in section, of the clutchingarrangement for actuating the coil spring clutch.

Referring now in detail to the drawings as disclosed in Figure l, thetransmission which has the drive gear thereof extending forwardly in theform of the shaft 58 is connected through either a planetary underdriveand fluid coupling or through any other clutching arrangement to thesource of power of the vehicle. The flanged end 18 of the transmissionhousing has formed therein a ball adapted to receive the bearings 11 forsupporting the rear end of the shaft 58. At its rear end within thehousing of the transmission the shaft is radially energized to providethe drive gear portion 82 and is axially recessed to receive the pilotend 83 of the main transmission shaft 84 which is journaled therein bymeans of the roller bearings 85.

Considering now the transmission housing structure as shown in Figure 1,the housing 18 of this mechanism is closed at its rear end by atransverse member |20 which has an offset bearing portion |22 adapted toreceive the ball bearing assembly |23 supporting the tail shaft 84 ofthe transmission. The other end of this shaft, as previously described,is piloted by the bearings 85 in the end of the drive shaft 58. Thedrive gear 82 of the shaft 58 has constant meshing engagement within thehousing |24 with a gear |25 mounted on the sleeve |26 by means ofsplines |21. The sleeve |26 is suitably supported upon bushings orthe'like on a counter shaft |28 supported at one end in the end I8 ofthe housing |24 and at the other end in a transverse web |28. Suitablethrust washers |38 at opposite ends of the sleeve retain it in position.Also splined upon the sleeve |28 is an axially movable gear member |32having at one end thereof the annular groove or yoke collar |33 forreceiving the shifting fork and having at its opposite end the reversespeed idler gear or low speed gear |34 of the transmission. The member|32 is adapted to be shifted axially on the splines |35 of the sleeve|26 and when shifted axially to the right of the position shown inFigure 1.is adapted to have meshing engagement with the teeth |36 of thegear |31 which is suitably mounted by means of studs |38 upon the radialflange |39 of a hub member |48 suitably supported for rotation by meansof bushings upon the shaft 84. Between the gear |31 and the gear 82 theshaft 84 is splined as indicated at |42 to receive the splined hubportion |43 of a synchronizing mechanism including an outersynchronizing sleeve |44 and internally splined to the hub |43 andadapted to have axial sliding movement and coupling engagement with theclutch teeth |45 of the gear 82 whereby the sleeve |44 clutches betweenthe gear 82 and the hub portion |43 to directly couple the shafts 58 and84 for driving engagement.

The enlarged end of the shaft 58 is also provided with a frictionsurface |46 adapted -to be engaged by the friction cone |41. carried bythe synchronizing portion |48 of the clutch |44. The ring or cone isnormally urged into frictional engagement with the surface |46 by meansof axially directed springs |49 carried within the hub member andbearing against the inner anged end of the member |46. This particularsynchro nizing structure is similar to that described in the copendingapplication of O. K. Butzbach, Serial No. 343.938, led July 5, 1940. Thetoothed portion |50 of the hub member |43 has formed therein atcircumferentially spaced points the poppet balls |52 which are adaptedto engage in suitable recesses |53 formed in the internal splines of thesleeve |44 to act as detents therefor whereby inltial shifting movementof the member |44 will carry the hubv |43 axially to the left to bringthe friction surfaces |46 and |41 into positive engagement forsynchronizing the speeds of the shafts 84 and 58 prior to moving theclutch sleeve |44 into clutching engagement.

Suitably mounted upon the splines |55 of the shaft 84 is the hub portion|56 of a. gear member |51 which has-external gear teeth |58 formedadjacent the gear teeth |36 and spaced therefrom by means of the thrustWasher |59. The external axially directed portion of the member |51 hasbearing engagement on the cylindrical portion |31 of the gear |36 bymeans of a bushing |60. Mounted within the annular space between the endof the cylindrical portion |31 of the gear |36 and the end ange of themember |51 is an annular ring |62 which is secured to the member |51 bymeans of the rivets |63. This member forms an internal cylindricalbearing surface to be acted upon by the coils of the helical springclutch |64. This-clutch |64 is anchored at one end as indicated at |65in Figures 1 and 5 in the end portion of the member |51 and extendsaxially between the hub |56 and the member |51 and the ring |62 andthence into the annular space between the sleeve |48 of the member |38and the inner surface or annular portion of the gear member |31. At itsinner end the coil spring member is provided with a normally |84adjacent the rear end |85 of the housing |88.`

directed lip |66 which is `adapted to |be .engaged by the radiallyinturned end of a sleeve member |61 carried within the gear member |31and retained in position therein by means of the snap ring |68.

Mounted upon suitable dowels and studs |12 carried by the flangedportion l|69 of the member |40 is a radial plate member |13 which isnormally spring-pressed toward the synchronizer sleeve |44 by means ofsprings |14. The inner end of the studs |112 have secured thereto theannular sleeve member which at its inner end is provided with'therecessed or notched portion |16 shown in Figure 5. When the synchronlzersleeve |44 is shifted to the right, as viewed in Figure 1, it abutsagainst the plate |13 thereby urging the sleeve |15 axially to the rightto move the notched portion |16 thereof into engagement with the end |66of the spring |64. Under such conditions, if the tail shaft 84 isrotating at a faster speed than the engine with the ilrst speed gear |34in meshing engagement with the gear |36 there will bea difference inrelative rotation of the member |51 and the gear member |31 which, inturn, results in a diiference in rotation between the member |51 and themember |40 secured to the gear member and carrying the sleeve |15. Thisresults in contraction of the spring coils thereby locking the spring|64 to the external annular surface of the member |40 and providingpositive clutching engagement between the member |51 and the member |40to produce a braking action when, and if, desired so that the engineacts as a brake upon the tail shaft.

With the plate member |13 in the position shown in Figure 1 there is notendency to contract the coils of the spring |64 and, consequently,these springs will remain in a normal intermediate position in which themember |31 will not be clutched with the member |51. However, when thefirst speed gear |34 is moved into meshing engagement with the gearteeth |36 and is driven by the shaft 58 it will tend to rotate the gear|36 at a speed greater than the speed of the member |51 since this isthe low speed drive through the transmission. As afresult the teaserspring |18 will act through the member |61 to energize the coils of thespring |64 in the opposite direction expanding the same to produce aclutching action between the internal annular surface of the gear member|31 and the internal annular surface of the ring |62 secured to themember |51. As a result, as long as the member |31 tends to overdrivethe member |51 there will be a positive clutching action caused byexpansion of the spring coils and a positive drive to the shaft throughthe splines |55 will be produced.

However, the shaft 84 tends to overrun with respect to the driving gears|34 and |36, during release of the accelerator prior to shifting. Thespring |64 then returns to a neutral position allowing the shaft 84 tooverrun relative to the gear |36 so that there is no momentary brakingaction of the engine during this interval. This overrunning action willbe effected as long as the first speed gear is in engaged position withthe gear |36 regardless of whether the direct or underdrive is providedthrough the planetary.

The housing |24 has secured to the rear end thereof the conical housing|80 having a flange |82' secured through the intermediate member to theend of the housing |24 by means of studs |83. 'I'he tail shaft 84extends through the housing |80 and is suitably supported adjacent itsrear end by means of the bearing assembly The projecting end of theshaft 84 indicated at |86 is splined to receive the companion flange ofa universal joint assembly .which connects the tail shaft to thepropeller shaft. Disposed within the housing the shaft 84 is providedwith a speedometer gear |81 of conventional design and is also providedwith a governor mechanism comprising a fixed portion |88 keyed to theshaft 84 and carrying the opposite pivots |89 which through the links|90 are connected to the toggle joints |92acting as the centrifugallymovable members of a governor mechanism connected through the oppositepair of links |93 to pivots |94 carried on a yoke collar |95. It will beapparent that as the speed or rotation of the shaft 84 increases thetoggle joints |92 move radially outwardly under the influence ofcentrifugal force, thereby tending to move the yoke |85 axially to theleft along the shaft 84. This results in compression of the double coilsprings |96 and |91 which resist this movement and which can be adjustedto control the point atwhich the yoke collar will move sufficiently toactuate suitable valving mechanism for controllingv the shifting withinthe. transmission.

Referring again to the two speed transmission of Figure 1, an idlershaft 200, shown in Figure 4, is provided within the transmissionhousing and carries thereon an externally splined sleeve |99 slidablyreceiving the gear 202 which has a yoke portion 20| for receiving ashift fork. The gear 202 is an idler gear carried on the shaft 200 andwhen moved to the left from the position shown in Figure 1, is adaptedto have meshing engagement with the gear teeth |58. Theopposite end ofthe shaft sleeve |99 has a fixed gear 203 adapted to be driven by thegear 34 when in the position shown in Figure 1, whereby the gear |51 isdriven in a reverse direction when the gear 202 is shifted to the leftfrom the position shown in Figure 1 into meshing engagement with thegear |58. This results in providing reverse drive through thetransmission to the tail shaft as indicated at |55. This reverse driveis independent of the spring clutch and provides a positive reverse fromthe gear |34 to the gear 203 and thence through the gear 202 to the gear|58. Thus there is no overrunning or free wheeling in reverse drive.

In the form of the invention shown in Figure 2 the spring clutch iseliminated and a more or less conventional type of overrunning clutchindicated at 205 is inserted between the gear |36' and the gear |58'.The gear |58' in this form of the invention is provided with a radiallyflanged end portion 206 which is rigidly secured as at 201 to a hubmember 208 mounted on the splines |55 of the tail shaft 84. The member208 also has a clutch journal surface 209 forming the inner race for theoverruning clutch 205. The overrunning clutch 205 is mounted in aretainer 2|0 carried within and preferably cast integrally with abearing support 2|2 which at one end forms a thrust flange 2'|3 betweenthe flanged portion of the hub member 208 and the cylindrical extension2|4 of the gear member 2| 5 carrying the gear teeth |36. The retainingmember 2|2 is locked by means of splines or the like for limitedrotation relative to the hub member 208 and a suitable coil spring 2| 6normally urges the clutch assembly into inoperative position. g

The gear member 2 5 is provided with a clutch toothed portion 2| 1adapted to be engaged by the synchronizer sleeve |44 having the internalteeth mounted on the external toothed portion of the synchronizer hub|43 mounted on the splines |42. Disposed axially upon the clutch teeth2|'| the gear member 2 5 has a friction clutch surface 2|8 adapted to beengaged by a synchronizing cone 2|9 carried by the synchronizer hub |43.It will thus be apparent that the synchronizing sleeve |44 can beshifted to the right as viewed in Figure 2 to provide a positive clutchbetween the shaft 84 and the gear member 2 I 5. Thus a positive lowspeed drive can be provided, if desired. However, in normal operationthe gear |34 on the countershaft |28 will drive the gear |36' whichthrough the overrunning clutch 205 will pick up and drive the hub member208 for driving the tail shaft.

Whenever the tail shaft begins to rotate faster than the gear |36 theclutch will function to release engagement therebetween and allow a freewheeling action. lThe reverse gearing is operated in this form of theinvention in the same manner as described in connection with Figure 1.The positive clutch between the gear |36 and the shaft 84 is for thepurpose of being able to crank the motor by moving the vehicle andprovides a construction corresponding to that shown in the copendingGreenlee application, Serial No. 358,393, i'lled September 26, 1940.

In the construction shown in Figure 3 the mechanism is substantially thesame as shown in Figure 1 with the exception that the gear teeth |58have been removed from the member |51. This then requires that thereverse slider 202 be moved to the left so that it canV be moved intoclutching engagement with the gear |36 instead of within the gear |58.The spring clutch arrangement functions in exactly the same manner aspreviously described, allowing the gear |38 to couple to the shaftthrough the member |51 by expansion of the clutch coils and to beuncoupled from the member |51 when this member tends to overrun the gear|36. The advantage of such a construction is the elimination of the gearteeth |58 thereby reducing materially the cost of the construction andthe shortening of the shaft portions on which the reverse gears 202 and203 are mounted. It will be apparent that whenever the gear |34 isshifted into meshing engagement with the gear |36 in any of the forms ofthe invention shown in Figures 1 to 3, the lay shaft 200 will beuncoupled from any gearing engagement and, consequently, will not berotated. This-is of distinct advantage. One of the distinctions betweenthe construction shown in'Figure 1 and that shown in Figure 3 is thefact that the reverse drive in the latter form of the invention iscoupled to the tail shaft 84 through the spring clutch |64, this clutchbeing reversely energized under such conditions to provide the couplingengagement.

The shifting mechanism for the gears |34 and 202 is shown somewhatdiagrammatcally in Figure 4. It will be seen that the transmissionhousing |24 is provided with a side opening. indicated at 220. Disposedin vertically spaced arrangement within this opening are the shift rails222 and 223 mounted in suitable journals formed in the transmissionhousing. Each of the shift rails is provided with a shifter forkindicated at 224 and 225 having projecting notched lfg portions 226 and221, respectively, adapted to be engaged by any suitable actuating meansfor shifting the fork and rail axially to move the respective gears intothe desired position. The shifter forks 224 and 225 have yoke portionsengaged in the corresponding collars 20| and |33 of the respective 75gears. Preferably the transverse web or partition 228 formed in thetransmission housing for supporting the lay shaft 200 is provided with asuitable pin member 229 extending longitudinally of the transmission andproviding a support for the notched portion 230 of the shifter fork 224to maintain it in position without imposing any radial stress upon theyoke portion 20| of the gear 202. The particular mechanism by which theforks 224 and 225 are shifted forms no part of the present invention butsuflice it to say that the actuating means is hydraulically controlledby means of suitable valves and pistons which are operated in accordancewith the governor mechanism shown in Figure 1, so far as shifting theclutch sleeveA |44 is concerned. So far as the reverse idler gear isconcerned, the shifting of this gear can be manually controlled by asimple lever which moves the gear into meshing engagement with eitherthe gear |36 or the gear |58 and when in its opposite position shiftsthe gear 202 into neutral position.

If it is desired to start the vehicle off in its lowest speed ratio thegear |34 in the transmission is shifted into meshing engagement with thegear |36 and is allowed to remain in this position throughout the normalforward driving range. This shift canA be controlled by a small lever onthe steering column which merely is shifted in one direction to effect aforward drive and in the opposite direction is operable to shift thegear 202 into engagement with the gear |58. The remainder of the drivecan be automatic in operation. The engine then drives the shaft 58 whichthrough the counter shaft |35 and the gear |34 drives the gear |36 inthe transmission. This gear is free to rotate relative to the shaft 84but as it starts to overrun with respect to the gear |51 the spring |64is energized, thereby effecting a friction clutching engagement betweenthe gears |38 and |51 so that the drive is transmitted to the main shaft84.

As the speed of this shaft increases, the governor mechanism in thehousing begins to function, moving the shift cenar to the left.

This, in turn, operates a suitable valve mechanism in a iiuid controlledcircuit for shifting the synchronizer sleeve |44 into engagement withthe clutch teeth |45 of the gear 82, thereby producing a direct drivebetween the shafts 58 and 84. This-direct drive can be effected whilethe gear |34 remains in meshing engagement with the gear |36 since thegear |31 is free to overrun relative to the gear |56.

It is to be understood that the particular control means and theparticular sequence of the drives can be varied as desired. For example,the drive can be an underdrive through the planetary and a reductionthrough the transmission then a shift to a direct drive through theplanetary with a reduction through the transmission and a subsequentdirect drive eliminating the reduction change in the transmission.Optionally, the drives could be arranged to provide an underdrivethrough the planetary with a reduction through the transmission. then ashift to direct drive in the transmission and a final shift into directdrive through the planetary. Thus, by properly arranging the controlsystem the present construction is capable of a combination 'ofdifferent driving ratios, available for use and controlled in accordancewith the torque and speed conditions encountered.

If it is desired to effect reverse drive, the gear |34 while in neutralis in constant mesh with the gear 203 of lay shaft 260. The gear 232 isthen shifted into engagement with the gear |58 whereby upon actuation ofthe clutch 50 reverse drive can be effected to the gear |51 and thenceto the shaft 84 either in underdrive or direct drive through theplanetary although preferably this will be arranged to operate throughthe underdrive of the planetary.

If it is desired to use the motor as a brake, as, for example, comingdown hill, the synchronizer sleeve Mii can be shifted rearwardly toengage the plate |13 which, in turn, through the sleeve H energizes thespring |64 in a reverse direction thereby coupling the gear |51 to thegear |36 and consequently coupling the shaft tt back through thereduction gearing to the engine through the fluid coupling to provide anengine brake for retarding the speed of the vehicle when coasting. rThiscan be either manually or automatically controlled.

The forms of the invention shown in Figures 2 and. 3 will providesimilar operating sequences, the only difference between Figure 1 andFigure 2 being the use of an overrunning clutch 205 in piace of thespring Hifi and the provision of means for directly coupling the gearE35 to the shaft 8F; in place of using the plate H3 and reversing theenergization of the spring |64.

In Figure 3 a construction substantially identical with Figure l isprovided, except that the teeth ld of the member |51 are eliminated andthe reverse gear 202 is adapted to be shifted directly into engagementwith the gear |36. In its other respects, this construction is the samein so far as the operating sequences are concerned.

It is therefore believed apparent that we havel provided a novel type oftransmission which is` capable of automatic operation and which providesall the various driving ratios necessary to utilize the transmissionunder various conditions.

We are aware that numerous changes may be made in certain details ofconstruction of the present invention and in details of the variouselements disclosed in the instant application and we therefore do notintend to be limited except as defined by the scope and spirit of theappended claims.

We claim:

1. In a transmission, a main shaft, a gear rotatably journalled thereon,a second gear splined on said shaft and having a portion overlying thehub on the rst gear, a countershaft, a gear on said countershaftslidable into driving engagement with said rotatable gear, a coiledspring member lying between the overlying portions oi said main shaftgears, means operable to actuate said coils ofthe spring member tofrictionally clutch said gears for conjoint rotation when said rotatablegear tends to overrun said splined gear, shiftable means on saidmainshaft, and means for actuating said coiled spring member in areverse direction upon actuation of said shiftable means to clutch saidrotatable gear to said splined gear when said shaft overruns saidrotatable gear.

2. In combination, in a transmission, a drive gear, a main shaft havingone end journalled in said drive gear, a countershaft, gear means onsaid countershaft driven from said drive gear, a gear rotatablyjournalled on said main shaft, a gear splined on said main shaftadjacent said rotatable gear, overrunning spring clutch means betweensaid main shaft gears, a countershaft gear shiftable into engagement,with said rotatable gear for driving said main shaft through said clutchmeans at a speed reduction, shiftable means on said main shaft, meansfor actuating said overrunning spring clutch in a reverse direction uponactuation of said shiftable means to clutch said rotatable gear to saidsplined gear when said shaft overruns said rotatable gear, a lay shaft,a gear thereon driven from said shiftable countershaft gear when shiftedout of engagement with said rotatable gear, andy a shiftable lay shaftgear engageable with said splined gear to provide a positive reversedrive to said main shaft.

3. In combination, in a transmission, a main shaft, a gear rotatablethereon having an annular channel, a member splined on said main shafthaving an alined annular channel, means for driving said rotatable geara coiled friction spring in said channel anchored at one end tov saidmember, means operable upon overrunning said rotatable gear relative tosaid main shaft for energizing said spring to clutch said rotatable gearto said member, axially shiftable means on said main shaft selectivelyoperable to energize said spring in a reverse direction for clutchingsaid member to said rotatable gear when said shaft overruns saidrotatable gear, and a reverse idler engageable with said rotatable gearfor reversing the direction ofv rotation of said main shaft only whensaid axially shiftable means is actuated.

4. In combination, a transmission main shaft having a gear rotatablethereon, a countershaft includingan axially shiftable gear, a lay shaftnormally driven from said countershaft gear, said countershaft gearbeing shiftable to drive said rotatable gear, overrunning clutch meansfor clutching said rotatable gear to said main shaft, a shiftable gearon said lay shaft operable to move into engagement with said rotatablegear when said countershaft gear is driving said lay shaft to effectreverse drive of said rotatable gear; and means operable to actuate saidclutch means in lthe, reverse direction for clutching said rotat-J ablegear under reverse drive to said main shaft.

5. The combination of claim 4 further characterized in the provision ofdrive gear means for said countershaft .iournalling one end of said mainshaft, and means for clutching said main v shaft directly to said drivegear means independently of the position of said countershaft gear butonly when said lay shaft gear is in disengaged position.

HARRY R. GREENLEE. LOREN D. BRITTON. JOHN R. BOND.

